Method of adding extra filler to the edges of paper



Nov. 2, 1954 M. o. SCHUR METHOD OF ADDING EXTRA FILLER TO THE EDGES OF PAPER Filed April 10, 1951 IN VEN TOR.

W m m n a 4 0 .N m M M United States Patent Ofifice 2,693,415 Patented Nov. 2, 1954 METHOD 6F ADDING EXTRA. FILLER TO THE EDGES 6F PAPER" Milton O. Schur, Asheville, N. C., assignor to Ecusta Paper Corporation, a corporation of- Delaware ApplicationAprillll, 1951, SerialNo. 220,269

2 Claims. (CI. 9221) This invention relates to the method. of. increasing the filter content at selected locations in a. paper sheet. The

method may find utility in the manufacture of various types of paper where it is desired to introduce into the paper sheet, at any desired location, additional. amounts of filter. Also, the filler may be of various and sundry types, such as calcium. carbonate, magnesium carbonate, titanlum dioxide, clay, starch, etc., and all. of these varlatlons are intended to be includedwithin the scope of the present invention.

The invention has been found to have great utility and substantial commercial importance in the manufacture of cigarette paper, wherein the calcium carbonate this furnish is flowed onto. the. paper machine wire to form the paper sheet.

Heretofore, cigarettes wrapped in paper out from the center of the sheet at the reel of the paper machine have burned more rapidly than those wrapped in paper taken from the edges of the sheet. The difference in burning rate is directly proportioned to the d'iif'erence in porosity and this in turn is proportioned to the difference in calcium carbonate filler content at the center and edges of the sheet, respectively.

Heretofore, the paper machine operators attempted to maintain a delicate balance of quality by manufacturing a paper of higher average porosity than required so that the edges of the sheet would only be slightly deficient in porosity. However, this practice resulted in a paper that tended to burn too fast at the center of the sheet. By diverting a small amount of the main supply of the filler and directing it to the edges of the stream of stock flowing onto the Fourdrini'er; it has been found possible to eliminatev the difference in porosity between the edges and the center of the sheet. At substantially no extra cost, this method has greatly facilitated the control of the porosity, and hence of the burning rate, of the Example I During the manufacture of standard cigarette papercomprisedof flax pulp and precipitated chalk, paper sampled at about the center of the sheet as it was wound up at the reel weighed 20.88 grams per square meter, had a porosity of. 47, an opacity of. 72.5, a filler content of 25.5%, a tensile strength of 3.71 kilograms per 3 centimeters, and a stretch at break of 2.2%. Samples taken at the edge of the sheet averaged 21.88 grams per square meter in weight, in porosity, 71.5 in opacity, 24.0% in filler content, 3.99 kilograms per 3 centimeters in tensile strength, and 2.2% in stretch at break. The porosity was at the very edge, and 60 nine inches from the edges. Similarly, the opacity of the sheet was 70 at the edge of the sheet, and 71 about nine inches from the edge.

In order to improve the porosity and the opacity of the paper at and near the edge of the sheet, a carbonate slurry consisting of 12%. lbs. of calcium carbonate per 50 gallons was fed at. the. rate. of about 0.85 gallon per minute at a point approximately 14" behind the slice through a shower pipe having holes on' 1" centers. The outermost. hole was about /2" from the edge of the pond behind the slice. The speed of the paper machine during this: run was meters per minute. After the extra. filler was added, the porosity at the edge of the sheet averaged 47, the weight of the paper 21.86 grams per square meter, the opacity 73.0, the filler content 27.3%,. the. tensile strength 3.53 kilograms per 3 centimeters, and the stretch 2.1%. Samples of paper taken from the middle of the sheet showed a porosity'of 47, weight of 2 1 .18, opacity of 72.8, filler content of 25.7%, tensile strength of 3.72 kilograms per 3' centimeters, and stretch of 2.1%.

Thesedata are collected. below. By porosity is meant the time in seconds for a given volume of air to flow throughthe paper specimen under standardized conditions: the lower thevalue the more porous the sheet. Opacity was: measured by means of a Photovolt reflectometer: the lower the val'ue,, the less opaque the sheet.

pearance to the middle of the sheet.

cigarette papenand. has practically eliminated the danger of paper with. off-quality porosity getting out to the trade.

Average Edge Values Average Center- Beforev During Values Addition Addition or Extra; ofExtra Filler Filler 20.88 21. 88- Y 21.86 41 65 47' 72.5 71. 5- 73. 0 2515 24.0 273 3. 71 3.99 3.53 Stretch 2.2 2.2 2.1

porosity and the opacity without serious impairment of the strength" of' the paper and without excessive change inweight. This is avery important: result, since it. shows that the extra filler added at the. edges makes the edges of the paper equal in combustihility and in. general ap- Av difference in porosity between 65 and 47 indicates a marked difierence in rate of combustibility; Thus, a cigarette rolled in cigarette paper with a porosity of 65 would burn much more slowly than when the same tobacco is rolled in cigarette paper having'a porosity of 47.

Example II In: another example ofi procedure; about 0.58 gallon per minute of carbonate slurry of the same strengthused in' the foregoing example of' procedure was simllarly added to the edge of the pond. Thedata observed are as follows;

Average Edge Values Average Center Before During Values Addition Additl' n of Extra. of Extra Filler Filler Weight 21.18 1 21.8 22 12 Porosity. 47 61 51 Opacity 72. 8 72; 3 72. 2 Filler Content 25.7 24.8 26. 2 Tensile... 3. 72 3. 86 3. 47 Stretch 2. l 2. 1 2. 1

1 in this experiment, as in. the first, it isapparent that the extrafiller added to the edge of the sheet improved the porosity without serious loss in strength.

Example III In a third example of procedure, a slurry containing 0.24 lb. of filler per gallon was added at the rate of 0.31 gallon per minute to distributing showers at each edge of the machine flow box. Below are listed the data observed.

Front Edge Back Edge Averages Averages Before During Before During Addition Addition Addition Addition of Extra of Extra of Extra of Extra Filler Filler Filler Filler Example IV In a fourth example, the conditions were similar to those in the previous example. The data observed are The above front and back edges refer, respectively, to the front and "back side of the paper machine as commonly termed by the machine attendants.

Example V A slurry containing about of a pound of filler per gallon was added at the edges of the paper machine fiow box through two narrow troughs set at right angles to the direction of travel of the Fourdrinier wire. The troughs were about 6" long, 4" wide, and 8 deep, and were provided at the bottom with six holes on 1" centers. The hole nearest the edge of the flow box was diameter, the second hole from the edge was ,4 in diameter, the third and the other three holes were each 34, diameter. The reason for the variation in hole diameter was to permit increased proportion of carbonate to be added at the very edge of the flow box. About 0.7 of a gallon per minute of slurry was added to each of the distributing boxes. The results obtained are summarized in the following table.

Center of Sheet Averages Front Edge Back Edge Averages Averages Before During Before During Before During Addi- Addi- Addi- Addi- Addi- Addition of tion of tion of tion of tion of tion of Extra Extra Extra Extra Extra Extra Filler Filler Filler Filler Filler Filler in Example V above, and which are supplied with spaced holes in the bottom to provide more or less separate small streams of the calcium carbonate slurry indicated at 14 and 15. These troughs 12 and 13 are located above and near the corners, at the rear, of the flow box 16, which contains the pool of paper furnish 17. A fixed slice 18 and a flexible slice 19 are provided for controlling the flow of the furnish onto the machine wire. The desired quantity and concentration of the additional calcium carbonate filler 19, is furnished, through the pipes 10 and 11, from a source of carbonate supply (not shown) and is fed by any suitable type of supply and metering device to provide a uniform flow of the slurry. The source of carbonate supply for these edge additions may be the same as the supply of carbonate to the entire furnish, or it may be a separate supply.

The additional calcium carbonate filler slurry 14 and 15 is incorporated into the pool of paper furnish 17 and tends to distribute itself quickly and uniformly in the furnish, although leaving the predominant amount of the added calcium carbonate filler within the relatively narrow area where it is introduced. This method of addition causes no streaks in the paper sheet formed from this furnish, and the paper sheet is substantially the same in appearance as that produced on this type of machine without these edge additions of the calcium carbonate filler, except for the improved opacity which is effected at the edges of the sheet by the method of this invention.

Various changes and modifications may be made in the above-described materials, method and equipment without departing from the scope of this invention as defined in the appended claims.

I claim:

1. A method of improving the uniformity of distribution of the carbonate filler in a cigarette paper sheet produced on the forming wire of a paper machine, from a pulp and filler furnish supplied from a head box, comprising adding additional amounts of carbonate filler to the furnish in the head box at locations adjacent the edges thereof and in line with the edges of the forming wire, the amount of added filler being suificient to make the carbonate filler content at the edges of the paper sheet substantially equivalent to the carbonate filler content at the center of the sheet.

2. A method of avoiding the usual deficiency of filler content at the edges of a filled paper sheet produced on the forming wire of a paper machine, comprising adding controlled amounts of filler slurry to the pulp and filler furnish in the paper machine head box at locations adjacent to the edges of the head box in line with the edges of the paper sheet produced on the forming wire, the added amounts of filler blending with the pool of furnish in the head box and although leaving the predominant amount of the added filler within the relatively narrow areas where it is introduced, nevertheless causing no streaks in the paper sheet formed from said furnish.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 254,929 DArgy Mar. 14, 1882 328,300 Susini Oct. 13, 1885 1,039,413 Klee Sept. 24, 1912 1,790,822 Ledeboer Feb. 3, 1931 1,803,642 Rafton May 5, 1931 1,811,613 Clapp June 23, 1931 2,033,481 Richter Mar. 10, 1936 2,189,832 Rafton Feb. 13, 1940 2,265,455 Serpas Dec. 9, 1941 OTHER REFERENCES 5llvgzcDonald, Paper Trade 1., April 11, 1929, pages 

2. A METHOD OF AVOIDING THE USUAL DEFICIENTY OF FILLER CONTENT AT THE EDGES OF A FILLED PAPER SHEET PRODUCED ON THE FORMING WIRE OF A PAPER MACHINE, COMPRISING ADDING CONTROLLED AMOUNTS OF FILLER SLURRY TO THE PULP AND FILLER FURNISH IN THE PAPER MACHINE HEAD BOX AT LOCATIONS ADJACENT TO THE EDGES OF THE HEAD BOX IN LINE WITH THE EDGES OF THE PAPER SHEET PRODUCED ON THE FORMING WIRE, THE ADDED AMOUNTS OF FILLER BLENDING WITH THE POOL OF FURNISH IN THE HEAD BOX AND ALTHOUGH LEAVING THE PREDOMINANT AMOUNT OF THE ADDED FILLER WITHIN THE RELATIVELY NARROW AREAS WHERE IT IS INTRODUCED, NEVERTHELESS CAUSING NO STREAKS IN THE PAPER SHEET FORMED FROM SAID FURNISH. 